Manual disabling switch for rail vehicle automatic brake activator - allows train to pass faulty signal blocked in stop position by using two timers, comparator and AND=gate

摘要

The switch allows an automatic brake activator (F) to be over-ridden and has an associated timer (Z2) defining an interval after which the manual over-ride is released to allow subsequent operation of the brake activator. A second timing device (Z2) is activated at the same time as the first timing device (Z1) and defines a longer time interval during which the over-ride for the braking initiator is blocked. Pref. the disabling switch has a manual push-button (T) coupled to a store (S) and activating the 20 second timer (Z1) and the 30 second timer (Z2). A comparator (V) is coupled to both counters or timers (Z1,Z2) and triggers a fault indicator (M) when their count values differ. The output of the store (S) and the second counter (Z2) are coupled to an AND-gate (U) for disabling the brake activator.